`x-1/9 =8/3`
`=>x=8/3 +1/9`
`=> x= 24/9 +1/9`
`=>x= 25/9`
Vậy `x=25/9`
__
`x-2/20=-5/2-x`
`=>x+x=-5/2 +2/20`
`=> 2x= -50/20 +2/20`
`=> 2x= -48/20`
`=> x= -12/5:2`
`=>x=-12/5 xx1/2`
`=>x= -12/10`
`=>x= -6/5`
Vậy `x=-6/5`
`@` `\text {Ans}`
`\downarrow`
`a)`
Đề là \(\dfrac{x-1}{9}=\dfrac{8}{3}\) phải hongg bạn?
\(\dfrac{x-1}{9}=\dfrac{8}{3}\)
`=>` `(x-1)3 = 8*9`
`=> (x-1)3=72`
`=> x-1=72 \div 3`
`=> x-1=24`
`=> x=25`
`b)`
\(\dfrac{x-2}{20}=\dfrac{-5}{2-x}\)
`=>` `(x-2)(2-x)=20*(-5)`
`=> (x-2)(2-x)=-100`
`=> -[(x-2)(x-2)]=-100`
`=> -(x-2)^2 = -100`
`=> (x-2)^2 = 100`
`=> (x-2)^2 = (+-10)^2`
`=>`\(\left[{}\begin{matrix}x-2=10\\x-2=-10\end{matrix}\right.\)
`=>`\(\left[{}\begin{matrix}x=12\\x=-8\end{matrix}\right.\)
